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Crafty cuttlefish mimics male and female – at the same time

Too sexy for my body, on the right side only

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Male cuttlefish try to avoid fighting other males over mating rights, and new research from Macquarie University in Sydney has revealed the trick one species can play to look harmless: it can imitate male and female simultaneously.

Changing colours and patterns is well-known among sea creatures like cuttlefish, squid and octopus, but the Sepia plangon cuttlefish of Sydney Harbour takes it a step further: it can split its colouring down the middle to show male patterns on one side and female patterns on the other.

Researcher Culum Brown, an associate professor at Macquarie, told the Australian Broadcasting Corporation that "while displaying his super-cool male colours towards the girl,” the cuttlefish observed in the researchers’ tank “would be simultaneously pretending to be a female to other males”.

The side facing other males, on the other hand, was the motley brown pattern of a female.

That gender-bending marvel means it can try to hide its presence from a nearby male, while at the same time trying to look attractive to the female target of its affections.

The colour-split is best seen if you pause Culum Brown’s YouTube video at about eight seconds:

Not only is the colouring trick impressive in its own right, the researchers point out that it demands remarkable intelligence from the creatures: they only try the technique if it’s got a reasonable prospect of success. Brown says the trick is only attempted in the presence of a single competing male, when the half-male-half-female look mightn’t be detected. ®